Backlight module and lcd comprising the same

ABSTRACT

A backlight module comprises a backplate having a baseplate and side plates, a direct-lit LED array, edge-lit LED arrays and a light guide panel. The light guide panel is located above the baseplate. The direct-lit LED array is disposed between the baseplate and the light guide panel. The edge-lit LED arrays are disposed at two sides of the light guide panel and facing light incident surfaces thereof respectively. Light scattering structures for scattering light rays are disposed on a light exiting surface or on a bottom surface of the light guide panels. With the LED arrays and the light scattering structures, the light guide panel is divided into three backlight regions. Displaying of the backlight module is controlled region by region by the light scattering structures and the LED drive circuit to improve the brightness of the backlight module and reduce the power consumption of the liquid crystal module.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of non-provisional application No. 13/376,837,filed on Dec. 7, 2011 and entitled “BACKLIGHT MODULE AND LCD COMPRISINGTHE SAME”.

BACKGROUND

1. Technical Field

The present disclosure relates to the technical field of liquid crystal5 displaying, and more particularly, to a backlight module and a liquidcrystal display (LCD) comprising the same.

2. Description of Related Art

LCDs currently available all comprise a liquid crystal module and abacklight module adapted to provide backlight for a liquid crystal panelof the liquid crystal module. Because the liquid crystal panel does notemit light by itself, the backlight module must provide a uniform lightsource having adequate brightness to the liquid crystal panel so thatthe liquid crystal panel operates to display an image normally.

However, conventional liquid crystal modules using backlight have aninvariable power consumption during operation; that is, brightness ofthe backlight cannot be adjusted according to brightness of an image tobe displayed by the liquid crystal module. In other words, thebrightness of the backlight cannot be adjusted region by region, andthis is unfavorable for energy saving.

Some backlight structures which can adjust the brightness region byregion have been proposed. Such backlight structures generallyaccomplish adjustment of the brightness region by region by splicinglight guide panels together. However, this way of splicing light guidepanels together causes problems of nonuniform brightness andchromaticity at splicing gaps.

SUMMARY

The primary objective of the present disclosure is to provide abacklight module and a liquid crystal display (LCD) comprising the same,which are intended to reduce the power consumption of the liquid crystalmodule and improve the effect of adjusting the backlight region byregion.

To achieve the aforesaid objective, the present disclosure provides abacklight module, which comprises a backplate, a direct-lit LED array,edge-lit LED arrays and a light guide panel. The backplate comprises abaseplate and side plates. The light guide panel is located between theside plates of the backplate and above the baseplate. The direct-lit LEDarray is disposed on the baseplate of the backplate and located beneatha middle portion of the light guide panel. The edge-lit LED arrays aredisposed at two sides of the light guide panel and opposite to lightincident surfaces of the light guide panel respectively. A number oflight scattering structures for scattering light rays are disposed on alight exiting surface or on a bottom surface of the light guide panel atboth ends of the light guide panel adjacent to the edge-lit LED arrays.

Preferably, the bottom surface of the light guide panel comprises a leftregion, a middle region and a right region. The light scatteringstructures on the bottom surface of the light guide panel are disposedin the left region and the right region of the bottom surface. Themiddle region of the bottom surface faces towards the direct-lit LEDarray directly.

Preferably, a density of the light scattering structures disposed in theleft region and the right region of the bottom surface of the lightguide panel that are away from the edge-lit LED arrays is greater than adensity of the light scattering structures that are near the edge-litLED arrays.

Preferably, the light scattering structures on the bottom surface of thelight guide panel extend to an edge of an illuminating region of thedirect-lit LED array.

Preferably, the light exiting surface of the light guide panel comprisesa left region, a middle region and a right region. The light scatteringstructures on the light exiting surface are disposed in the left regionand the right region of the light exiting surface. The middle region ofthe light exiting surface faces towards the direct-lit LED arraydirectly. A density of the light scattering structures in the leftregion and the right region of the light exiting surface of the lightguide panel that are away from the edge-lit LED arrays is greater than adensity of the light scattering structures that are near the edge-litLED arrays.

Preferably, the light scattering structures on the light exiting surfaceof the light guide panel extend to an edge of the illuminating region ofthe direct-lit LED array.

Preferably, the light scattering structures are mesh point structures ormicro-protrusion structures, and a cross section of the light scatteringstructures is at least one of a hill form, a spherical form, atriangular form, an elliptical form and a diamond form.

Preferably, the light scattering structures on the bottom surface of thelight guide panel extend to an edge of the illuminating region of thedirect-lit LED array.

Preferably, the light scattering structures on the light exiting surfaceof the light guide panel extend to an edge of the illuminating region ofthe direct-lit LED array.

Preferably, two ends of the light guide panel formed with the lightscattering structures have a thickness greater than that of the middleportion of the light guide panel that is not formed with the lightscattering structures.

Preferably, the baseplate of the backplate is formed with a recessedportion and two supporting portions. The recessed portion is locatedbetween the two supporting portions and lower than the supportingportions. The direct-lit LED array is disposed on the recessed portion.

Preferably, the backlight module further comprises a reflective sheetdisposed on an upper surface of each of the supporting portions and inspaces between LEDs of the direct-lit LED array.

The present disclosure further provides an LCD comprising the backlightmodule as described above.

According to the backlight module and the LCD comprising the same of thepresent disclosure, the direct-lit design and the edge-lit design areused in combination in the backlight module, and a number of lightscattering structures for scattering light rays are disposed on thelight exiting surface or the bottom surface of the light guide panel atboth ends of the light guide panel to divide the light guide panel intothree backlight regions. By using the light scattering structures todisrupt the total reflection of light rays inside the light guide panel,regions illuminated by the backlight from the edge-lit LED arrays arecontrolled by the light scattering structures on the light guide panelwhile a region illuminated by the backlight from the direct-lit LEDarray is controlled by the LED drive circuit. In this way, the effect ofadjusting the brightness of the backlight of the backlight module regionby region is improved and the power consumption of the liquid crystalmodule is reduced.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of a first embodiment of abacklight module according to the present disclosure;

FIG. 2 is a schematic structural view of a second embodiment of thebacklight module according to the present disclosure; and

FIG. 3 is a schematic structural view of a third embodiment of thebacklight module according to the present disclosure.

Hereinafter, implementations, functional features and advantages of thepresent disclosure will be further described with reference toembodiments thereof and the attached drawings.

DETAILED DESCRIPTION

It shall be understood that, the embodiments described herein are onlyintended to illustrate but not to limit the present disclosure.

Embodiments of the present disclosure mainly adopt the followingsolution: the direct-lit design and the edge-lit design are used incombination in the backlight module, and a number of light scatteringstructures for scattering light rays are disposed on a light exitingsurface or a bottom surface of the light guide panel at both ends of thelight guide panel to divide the light guide panel into three 10backlight regions. Regions illuminated by the backlight from theedge-lit LED arrays are controlled by the light scattering structures onthe light guide panel while a region illuminated by the backlight fromthe direct-lit LED array is controlled by the LED drive circuit. In thisway, the effect of adjusting the brightness of the backlight of thebacklight module region by region is improved and the power consumptionof the liquid crystal module is reduced.

As shown in FIG. 1, there is shown a schematic structural view of afirst embodiment of a backlight module according to the presentdisclosure. The first embodiment of the present disclosure provides abacklight module which can control brightness of backlight region byregion. The backlight module is an incident backlight module in whichthe edge-lit design and the direct-lit design are used in combination.The backlight module comprises a backplate 1, a direct-lit LED array 5,edge-lit LED arrays 4, a reflective sheet 3 and a light guide panel 2.

The backplate 1 comprises a baseplate and side plates extending upwardsfrom a periphery of the baseplate. A middle portion of the baseplate isrecessed to form a recessed portion, and two sides of the recessedportion form a supporting portion respectively.

The light guide panel 2 is disposed above the baseplate of the backplate1, and the direct-lit LED array 5 is disposed on the recessed portion ofthe baseplate of the backplate 1. Specifically, the direct-lit LED array5 is located between the light guide panel 2 and the recessed portionand fixed on recessed portion.

The reflective sheet 3 is disposed on the supporting portions of thebaseplate of the backplate 1 and adapted to reflect light rays. In orderto better 5 reflect the light rays, the reflective sheet 3 is alsoprovided in regions between LEDs of the direct-lit LED array 5.

The light guide panel 2 has an upper surface, a lower surface and twoside surfaces. The upper surface of the light guide panel 2 is a lightexiting surface 23, the lower surface is a bottom surface 22 opposite tothe light exiting surface 23, and the two side surfaces are lightincident surfaces 21 at two sides of the light guide panel 2.

The edge-lit LED arrays 4 are disposed at the two sides of the lightguide panel 2 and opposite to the light incident surfaces 21 of thelight guide panel 2 respectively. The edge-lit LED arrays 4 aresupported on the supporting portions at two ends of the baseplate of thebackplate 1.

In this embodiment, a number of light scattering structures 6 aredisposed on the bottom surface 22 of the light guide panel 2 at bothends of the light guide panel 2 adjacent to the edge-lit LED arrays 4.The light scattering structures 6 are adapted to scatter light rays todisrupt the total reflection of light rays inside the light guide panel2 so that the light rays can be projected outwards from the light guidepanel 2.

The light scattering structures 6 may be mesh point structures ormicro-protrusion structures, and a cross section of the light scatteringstructures 6 may be a hill form, a spherical form, a triangular form, anelliptical form, a diamond form or any other form that can disrupt thetotal reflection of light rays inside the light guide panel 2.

The light scattering structures 6 are distributed to divide the bottomsurface 22 of the light guide panel 2 into a left region 221, a middleregion 222 and a right region 223. The left region 221 and the rightregion 223 of the bottom surface 22 of the light guide panel 2 areregions formed with the light scattering structures 6; and the middleregion 222 of the bottom surface 22 of the light guide panel 5 2 is aregion that is not formed with the light scattering structures 6. Themiddle region 222 faces towards the direct-lit LED array 5 directly.

In this embodiment, the brightness of the backlight of the backlightmodule can be controlled region by region. Regions illuminated by thebacklight from the edge-lit LED arrays 4 are controlled by the lightscattering structures 6 in the left region 221 and the right region 223of the bottom surface 22 of the light guide panel while a regionilluminated by the backlight from the direct-lit LED array 5 iscontrolled by the LED drive circuit.

Furthermore, when the light rays travel inside the light guide panel 2,the intensity of the light rays is gradually weakened with the increasein distance. The intensity of the light rays inside the light guidepanel 2 adjacent to the edge-lit LED arrays 4 is stronger, and theintensity of the light rays away from the edge-lit LED arrays 4 isweaker. If the light scattering structures 6 on the bottom surface 22 ofthe light guide panel 2 have the same density at a position near thelight source and a position away from the light source, then the lightrays projected from the light guide panel 2 at the position near thelight source have a larger intensity than the light rays projected fromthe light guide panel 2 at the position away from the light source. Asviewed by human eyes, the position near the light source is bright andthe position away from the light source is dark.

Thereby, the densities of the light scattering structures 6 on thebottom surface 22 of the light guide panel 2 are set as follows in thisembodiment. The intensity of the light rays adjacent to the edge-lit LEDarrays 4 is stronger, and correspondingly, the light scatteringstructures 6 are distributed with a smaller density; and the intensityof the light rays away from the edge-lit LED arrays 4 is weaker, andcorrespondingly, the light scattering structures 6 are distributed witha larger density. In this way, when the light rays are projected fromthe light guide panel 2, the light rays have a uniform intensity at theposition near the light source and the position away from the lightsource, thereby improving the displaying effect of the liquid crystalpanel.

Additionally, in this embodiment, the light scattering structures 6 aredistributed on the bottom surface 22 of the light guide panel 2 at bothends of the 10 light guide panel 2 adjacent to the edge-lit LED arrays 4while the bottom surface 22 of the light guide panel 2 above thedirect-lit LED array 5 is not formed with the light scatteringstructures 6. According to this structural feature, the distance thatthe light emitted from the edge-lit LED arrays 4 travels is mainlyrelated with distribution of the light scattering structures 6 on thebottom surface 22 of the light guide panel 2. When the regionsilluminated by the edge-lit LED arrays 4 are controlled, the distancethat the light rays of the edge-lit LED arrays 4 travel in the lightguide panel 2 can be controlled by adjusting the distribution of thelight scattering structures 6 on the bottom surface 22 of the lightguide panel 2. Thereby, the light rays emitted by the edge-lit LEDarrays 4 can be controlled within a certain region.

Furthermore, the regions in which the mesh point structures ormicro-protrusion structures 6 on the bottom surface 22 of the lightguide panel 2 are located shall extend beyond a peripheral region thatcan be illuminated by light emitted from an outermost LED of thedirect-lit LED array 5. That is, the light 25 scattering structures 6 onthe bottom surface 22 of the light guide panel 2 shall extend to an edgeof an illuminating region of the direct-lit LED array 5. In this way,the brightness difference will not occur in a transition region betweenthe regions formed with the light scattering structures 6 and the regionthat is not formed with the light scattering structures 6 on the lightguide panel 2.

The region illuminated by the backlight from the direct-lit LED array 5is controlled by the LED drive circuit. For example, when a film orvideo is played, both an upper end and a lower end of a screen areusually normally 5 black. If the two normally black regions correspondto the operating regions of the edge-lit LED arrays 4 exactly, then thetwo edge-lit LED arrays 4 can be turned off to save electric energy.

The aforesaid structure of this embodiment allows the brightness of thebacklight to be controlled region by region. This can reduce the powerconsumption of the liquid crystal module and improve the backlightdisplaying effect of the backlight module.

Referring to FIG. 2, there is shown a schematic structural view of asecond embodiment of the backlight module according to the presentdisclosure. This embodiment is similar to the first embodiment except inthat: in this embodiment, in a left region 321, a middle region 322 anda right region 323 on a bottom surface 31 of a light guide panel 32, themiddle region 322 of the light guide panel 32 that is not formed withlight scattering structures 36 has a thickness smaller than that of theother two regions 321, 323 formed with the light scattering structures36; that is, a portion of the light guide panel 32 on which the middleregion 322 on the bottom surface 31 of the light guide panel 32 islocated has a smaller thickness, and portions of the light guide panel32 on which the left region 321 and the right region 323 are locatedeach have a larger thickness. This design can reduce the weight of theoverall backlight module without degrading the effect of adjusting the25 backlight region by region.

Others are the same as those in the first embodiment.

Referring to FIG. 3, there is shown a schematic structural view of athird embodiment of the backlight module according to the presentdisclosure. Similar to the first embodiment, this embodiment comprisesedge-lit LED arrays 14, a direct-lit LED array 15, a light guide panel12 and the like. This embodiment differs from the first embodiment inthat: in this embodiment, light scattering structures 16 are notdisposed on a bottom surface of the light guide panel 12, but aredisposed on a light exiting surface of the light guide panel 12 at bothends of the light guide panel 12 adjacent to the edge-lit LED arrays 14.Others are the same as those in the first embodiment.

It shall be appreciated that, in actual applications, the aforesaidthree embodiments may be combined with each other depending on actualrequirements in order to arrive at or better achieve the objective ofreducing the power consumption of the liquid crystal module andimproving the backlight displaying effect of the backlight module.

Furthermore, the present disclosure further provides a liquid crystaldisplay (LCD) comprising a backlight module. The backlight module may bethe backlight module described in the aforesaid embodiments, and willnot be further described herein.

According to the backlight module and the LCD comprising the same of thepresent disclosure, the direct-lit design and the edge-lit design areused in combination in the backlight module, and a number of lightscattering structures for scattering light rays are disposed on thelight exiting surface or the bottom surface of the light guide panel atboth ends of the light guide panel to divide the light guide panel intothree backlight regions. By using the light scattering structures todisrupt the total reflection of light rays inside the light guide panel,regions illuminated by the backlight from the edge-lit LED arrays arecontrolled by the light scattering structures on the light guide panelwhile a region illuminated by the backlight from the direct-lit LEDarray is controlled by the LED drive circuit. In this way, the effect ofadjusting the brightness of the backlight of the backlight module regionby region is improved and the power consumption of the liquid crystalmodule is reduced.

Furthermore, according to the present disclosure, the light scatteringstructures disposed on the light guide panel that are away from theedge-lit 5 LED arrays have a large density so that when the light raysof the edge-lit LED arrays are projected from the light guide panel, thelight rays have a uniform intensity at the position near the lightsource and the position away from the light source, thereby improvingthe displaying effect of the liquid crystal panel.

Additionally, according to the present disclosure, the regions of thelight guide panel in which the light scattering structures are locatedextend into an illuminating region of the direct-lit LED array so thatthe brightness difference will not occur in a transition region betweenthe regions formed with the light scattering structures and the regionthat is not formed with the light scattering structures on the lightguide panel.

What described above are only preferred embodiments of the presentdisclosure but are not intended to limit the scope of the presentdisclosure. Accordingly, any equivalent structural or process flowmodifications that are made on basis of the specification and theattached drawings or any direct or indirect applications in othertechnical fields shall also fall within the scope of the presentdisclosure.

What is claimed is:
 1. A backlight module, comprising a backplate, adirect-lit light emitting diode (LED) array, edge-lit LED arrays and alight guide panel, the backplate comprising a baseplate and side plates,the light guide panel being located between the side plates of thebackplate and above the baseplate, the direct-lit LED array beingdisposed on the baseplate of the backplate and located beneath a middleportion of the light guide panel; the edge-lit LED arrays being disposedat two sides of the light guide panel and opposite to light incidentsurfaces of the light guide panel respectively; wherein a number oflight scattering structures for scattering light rays are disposed on alight exiting surface of the light guide panel at both ends of the lightguide panel adjacent to the edge-lit LED arrays; the baseplate is formedwith a recessed portion and two supporting portions, the recessedportion is located between the two supporting portions and lower thanthe supporting portion, and the direct-lit LED array is disposed on therecessed portion; the light exiting surface of the light guide panelcomprises a left region, a middle region and a right region, the lightscattering structures are disposed in the left region and the rightregion rather than in the middle region, and the middle region withoutthe light scattering structures formed therein faces towards thedirect-lit LED array disposed on the recessed portion directly.
 2. Thebacklight module of claim 1, wherein a density of the light scatteringstructures disposed in the left region and the right region of the lightexiting surface of the light guide panel that are away from the edge-litLED arrays is greater than a density of the light scattering structuresthat are near the edge-lit LED arrays.
 3. The backlight module of claim1, wherein the light scattering structures on the light exiting surfaceof the light guide panel extend to an edge of an illuminating region ofthe direct-lit LED array.
 4. The backlight module of claim 1, whereinthe light scattering structures are mesh point structures ormicro-protrusion structures, and a cross section of the light scatteringstructures is at least one of a hill form, a spherical form, atriangular form, an elliptical form and a diamond form.
 5. The backlightmodule of claim 1, wherein the light scattering structures on the lightexiting surface of the light guide panel extend to an edge of theilluminating region of the direct-lit LED array.
 6. The backlight moduleof claim 1, wherein two ends of the light guide panel formed with thelight scattering structures have a thickness greater than that of themiddle portion of the light guide panel that is not formed with thelight scattering structures.
 7. The backlight module of claim 1, furthercomprising a reflective sheet disposed on an upper surface of each ofthe supporting portions and in spaces between LEDs of the direct-lit LEDarray.
 8. A liquid crystal display (LCD) comprising a backlight module,wherein the backlight module comprises a backplate, a direct-lit LEDarray, edge-lit LED arrays and a light guide panel, the backplatecomprises a baseplate and side plates, the light guide panel is locatedbetween the side plates of the backplate and above the baseplate, thedirect-lit LED array is disposed on the baseplate of the backplate andlocated beneath a middle portion of the light guide panel; the edge-litLED arrays are disposed at two sides of the light guide panel andopposite to light incident surfaces of the light guide panelrespectively, and a number of light scattering structures for scatteringlight rays are disposed on a light exiting surface of the light guidepanel at both ends of the light guide panel adjacent to the edge-lit LEDarrays; the baseplate is formed with a recessed portion and twosupporting portions, the recessed portion is located between the twosupporting portions and lower than the supporting portion, and thedirect-lit LED array is disposed on the recessed portion; the lightexiting surface of the light guide panel comprises a left region, amiddle region and a right region, the light scattering structures aredisposed in the left region and the right region rather than in themiddle region, and the middle region without the light scatteringstructures formed therein faces towards the direct-lit LED arraydisposed on the direct-lit LED array directly.
 9. The LCD of claim 8,wherein a density of the light scattering structures disposed in theleft region and the right region of the light exiting surface of thelight guide panel that are away from the edge-lit LED arrays is greaterthan a density of the light scattering structures that are near theedge-lit LED arrays.
 10. The LCD of claim 9, wherein the lightscattering structures on the light exiting surface of the light guidepanel extend to an edge of an illuminating region of the direct-lit LEDarray.
 11. The LCD of claim 8, wherein the light scattering structuresare mesh point structures or micro-protrusion structures, and a crosssection of the light scattering structures is at least one of a hillform, a spherical form, a triangular form, an elliptical form and adiamond form.
 12. The LCD of claim 8, wherein two ends of the lightguide panel formed with the light scattering structures have a thicknessgreater than that of the middle portion of the light guide panel that isnot formed with the light scattering structures.
 13. The LCD of claim 8,further comprising a reflective sheet disposed on an upper surface ofeach of the supporting portions and in spaces between LEDs of thedirect-lit LED array.
 14. A backlight module, comprising a backplate, adirect-lit light emitting diode (LED) array, edge-lit LED arrays and alight guide panel, the backplate comprising a baseplate and side plates,the light guide panel being located between the side plates of thebackplate and above the baseplate, the direct-lit LED array beingdisposed on the baseplate of the backplate and located beneath a middleportion of the light guide panel; the edge-lit LED arrays being disposedat two sides of the light guide panel and opposite to light incidentsurfaces of the light guide panel respectively; wherein a number oflight scattering structures for scattering light rays are disposed on alight exiting surface of the light guide panel at both ends of the lightguide panel adjacent to the edge-lit LED arrays; the light exitingsurface of the light guide panel comprises a left region, a middleregion and a right region, and the light scattering structures on thelight exiting surface are disposed in the left region and the rightregion rather than in the middle region; the middle region of the lightexiting surface corresponds to the direct-lit LED array directly. 15.The backlight module of claim 14, wherein a density of the lightscattering structures in the left region and the right region of thelight exiting surface of the light guide panel that are away from theedge-lit LED arrays is greater than a density of the light scatteringstructures that are near the edge-lit LED arrays.
 16. The backlightmodule of claim 15, wherein the light scattering structures on the lightexiting surface of the light guide panel extend to an edge of theilluminating region of the direct-lit LED array.
 17. The backlightmodule of claim 14, wherein the baseplate is formed with a recessedportion and two supporting portions, the recessed portion is locatedbetween the two supporting portions and lower than the supportingportion, and the direct-lit LED array is disposed on the recessedportion and corresponds to the middle region of the light exitingsurface.
 18. The backlight module of claim 14, wherein the lightscattering structures are mesh point structures or micro-protrusionstructures, and a cross section of the light scattering structures is atleast one of a hill form, a spherical form, a triangular form, anelliptical form and a diamond form.
 19. The backlight module of claim14, wherein two ends of the light guide panel formed with the lightscattering structures have a thickness greater than that of the middleportion of the light guide panel that is not formed with the lightscattering structures.